diff --git a/ports/unix/Makefile b/ports/unix/Makefile
index d966e71327..ec60d8d2ad 100644
--- a/ports/unix/Makefile
+++ b/ports/unix/Makefile
@@ -213,7 +213,7 @@ ifeq ($(HASCPP17), 1)
 else
 	CXXFLAGS += -std=c++11
 endif
-CXXFLAGS += $(filter-out -Wmissing-prototypes -Wold-style-definition -std=gnu99,$(CFLAGS) $(CXXFLAGS_MOD))
+CXXFLAGS += $(filter-out -Wmissing-prototypes -Wold-style-definition -std=gnu99 -std=gnu11,$(CFLAGS) $(CXXFLAGS_MOD))
 
 ifeq ($(MICROPY_FORCE_32BIT),1)
 RUN_TESTS_MPY_CROSS_FLAGS = --mpy-cross-flags='-mcache-lookup-bc -march=x86'
diff --git a/ports/unix/variants/coverage/mpconfigvariant.mk b/ports/unix/variants/coverage/mpconfigvariant.mk
index e9674a3ec2..e5d0f7e2d3 100644
--- a/ports/unix/variants/coverage/mpconfigvariant.mk
+++ b/ports/unix/variants/coverage/mpconfigvariant.mk
@@ -22,7 +22,6 @@ FROZEN_DIR=variants/coverage/frzstr
 FROZEN_MPY_DIR=variants/coverage/frzmpy
 
 SRC_QRIO := $(patsubst ../../%,%,$(wildcard ../../shared-bindings/qrio/*.c ../../shared-module/qrio/*.c ../../lib/quirc/lib/*.c))
-$(info SRC_QRIO = $(SRC_QRIO))
 SRC_C += $(SRC_QRIO)
 
 CFLAGS += -DCIRCUITPY_QRIO=1
diff --git a/py/mkrules.mk b/py/mkrules.mk
index 81dd961ac6..50f35ffb22 100644
--- a/py/mkrules.mk
+++ b/py/mkrules.mk
@@ -65,7 +65,7 @@ vpath %.cpp . $(TOP) $(USER_C_MODULES)
 $(BUILD)/%.o: %.cpp
 	$(call compile_cxx)
 
-QSTR_GEN_EXTRA_CFLAGS += -DNO_QSTR
+QSTR_GEN_EXTRA_CFLAGS += -DNO_QSTR -x c
 
 # frozen.c and frozen_mpy.c are created in $(BUILD), so use our rule
 # for those as well.
diff --git a/py/mpprint.c b/py/mpprint.c
index af485a50f2..df73587449 100644
--- a/py/mpprint.c
+++ b/py/mpprint.c
@@ -545,7 +545,12 @@ int mp_vprintf(const mp_print_t *print, const char *fmt, va_list args) {
             case 'p':
             case 'P': // don't bother to handle upcase for 'P'
                 // Use unsigned long int to work on both ILP32 and LP64 systems
-                chrs += mp_print_int(print, va_arg(args, unsigned long int), 0, 16, 'a', flags, fill, width);
+                #if SUPPORT_INT_BASE_PREFIX
+                chrs += mp_print_int(print, va_arg(args, unsigned long int), 0, 16, 'a', flags | PF_FLAG_SHOW_PREFIX, fill, width);
+                #else
+                print->print_strn(print->data, "0x", 2);
+                chrs += mp_print_int(print, va_arg(args, unsigned long int), 0, 16, 'a', flags, fill, width) + 2;
+                #endif
                 break;
             #if MICROPY_PY_BUILTINS_FLOAT
             case 'e':
diff --git a/py/objfun.c b/py/objfun.c
index 115957e09c..23698ad95c 100644
--- a/py/objfun.c
+++ b/py/objfun.c
@@ -182,7 +182,7 @@ qstr mp_obj_fun_get_name(mp_const_obj_t fun_in) {
 STATIC void fun_bc_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_fun_bc_t *o = MP_OBJ_TO_PTR(o_in);
-    mp_printf(print, "<function %q at 0x%p>", mp_obj_fun_get_name(o_in), o);
+    mp_printf(print, "<function %q at %p>", mp_obj_fun_get_name(o_in), o);
 }
 #endif
 
diff --git a/py/profile.c b/py/profile.c
index e5fb35f0ed..2e59b97703 100644
--- a/py/profile.c
+++ b/py/profile.c
@@ -68,7 +68,7 @@ STATIC void code_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t k
     const mp_raw_code_t *rc = o->rc;
     const mp_bytecode_prelude_t *prelude = &rc->prelude;
     mp_printf(print,
-        "<code object %q at 0x%p, file \"%q\", line %d>",
+        "<code object %q at %p, file \"%q\", line %d>",
         prelude->qstr_block_name,
         o,
         prelude->qstr_source_file,
@@ -202,7 +202,7 @@ STATIC void frame_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t
     const mp_raw_code_t *rc = code->rc;
     const mp_bytecode_prelude_t *prelude = &rc->prelude;
     mp_printf(print,
-        "<frame at 0x%p, file '%q', line %d, code %q>",
+        "<frame at %p, file '%q', line %d, code %q>",
         frame,
         prelude->qstr_source_file,
         frame->lineno,
@@ -950,7 +950,7 @@ void mp_prof_print_instr(const byte *ip, mp_code_state_t *code_state) {
 
     /* long path */ if (1) {
         mp_printf(&mp_plat_print,
-            "@0x%p:%q:%q+0x%04x:%d",
+            "@%p:%q:%q+0x%04x:%d",
             ip,
             prelude->qstr_source_file,
             prelude->qstr_block_name,
diff --git a/tests/extmod/uctypes_print.py.exp b/tests/extmod/uctypes_print.py.exp
index 63daefc848..b1c730d44f 100644
--- a/tests/extmod/uctypes_print.py.exp
+++ b/tests/extmod/uctypes_print.py.exp
@@ -1,4 +1,4 @@
-<struct STRUCT 0>
-<struct ERROR 0>
-<struct ARRAY 0>
-<struct PTR 0>
+<struct STRUCT 0x0>
+<struct ERROR 0x0>
+<struct ARRAY 0x0>
+<struct PTR 0x0>
diff --git a/tests/micropython/meminfo.py.exp b/tests/micropython/meminfo.py.exp
index a229a7fa4c..fb9eaa890a 100644
--- a/tests/micropython/meminfo.py.exp
+++ b/tests/micropython/meminfo.py.exp
@@ -6,7 +6,7 @@ mem: total=\\d\+, current=\\d\+, peak=\\d\+
 stack: \\d\+ out of \\d\+
 GC: total: \\d\+, used: \\d\+, free: \\d\+
  No. of 1-blocks: \\d\+, 2-blocks: \\d\+, max blk sz: \\d\+, max free sz: \\d\+
-GC memory layout; from \[0-9a-f\]\+:
+GC memory layout; from 0x\[0-9a-f\]\+:
 ########
 qstr pool: n_pool=1, n_qstr=\\d, n_str_data_bytes=\\d\+, n_total_bytes=\\d\+
 qstr pool: n_pool=1, n_qstr=\\d, n_str_data_bytes=\\d\+, n_total_bytes=\\d\+
diff --git a/tests/unix/extra_coverage.py.exp b/tests/unix/extra_coverage.py.exp
index 57f4b139f9..2cf48de142 100644
--- a/tests/unix/extra_coverage.py.exp
+++ b/tests/unix/extra_coverage.py.exp
@@ -15,8 +15,8 @@ false true
 abc
 %
 # GC
-0
-0
+0x0
+0x0
 # vstr
 tests
 sts